Integrated photonics device

Abstract

The present invention relates to an integrated photonic device ( 100 ) operatively coupleable with an optical element ( 300 ) in a first coupling direction. The integrated photonic device ( 100 ) comprises an integrated photonic waveguide ( 120 ) and a grating coupler ( 130 ) that is adapted for diffracting light from the waveguide ( 120 ) into a second coupling direction different from the first coupling direction. The integrated photonics device also comprises a refractive element ( 110 ) disposed adjacent the grating coupler ( 130 ) and adapted to refract the light emerging from the grating coupler ( 130 ) in the second coupling direction into the first coupling direction.

The invention claimed is: 
     
       1. An integrated photonic device operatively coupled with an optical element configured to guide light in a first coupling direction perpendicular to the integrated photonic device, the integrated photonic device comprising:
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate; 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the core layer of the waveguide into a second coupling direction different from the first coupling direction; and 
 a refractive element disposed adjacent the top surface of the core layer of the integrated photonic waveguide such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being integrated with the grating coupler and adapted to refract the light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating, 
 wherein the first coupling direction is perpendicular to an average plane of the substrate on which the waveguide is disposed. 
 
     
     
       2. A device according to  claim 1 , wherein the refractive element is a wedge-shaped element integrated with the grating coupler. 
     
     
       3. A device according to  claim 1 , wherein the grating coupler comprises a grating, and the refractive element is made in direct contact with the grating of the grating coupler. 
     
     
       4. A device according to  claim 1 , wherein the refractive element is integrally made in the integrated photonics device by directly forming the refractive element in the integrated photonics device. 
     
     
       5. A device according to  claim 1 , wherein the refractive element is made of a moldable material. 
     
     
       6. A device according to  claim 5 , wherein the refractive element is made of polymer. 
     
     
       7. A device according to  claim 1 , wherein the refractive element comprises a plurality of sub-elements, each sub-element being adapted for refracting part of the light emerging from the grating coupler in the second coupling direction into the first coupling direction. 
     
     
       8. A device according to  claim 1 , wherein the refractive element comprises a focusing refractive surface. 
     
     
       9. A device according to  claim 1 , wherein the optical element is a vertical cavity surface emitting laser. 
     
     
       10. A method for coupling light between an an integrated photonic device and an optical element configured to guide light in a first coupling direction, the integrated photonic device comprising:
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate; 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the waveguide into a second coupling direction different from the first coupling direction; and 
 a refractive element disposed adjacent the top surface of the core layer of the integrated photonic waveguide such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being integrated with the grating coupler and adapted to refract the light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating, 
 
       the method comprising:
 coupling light from the core layer of the integrated photonic waveguide through the grating coupler in the second coupling direction; and 
 refracting light emerging from the grating coupler in the second coupling direction into the first coupling direction using the refractive element integrated with the grating coupler, 
 wherein the first coupling direction is perpendicular to an average plane of the substrate on which the waveguide is disposed. 
 
     
     
       11. A method for coupling light between an integrated photonic device and an optical element configured to guide light in a first coupling direction, the integrated photonic device comprising:
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate; 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the waveguide into a second coupling direction different from the first coupling direction; and 
 a refractive element disposed adjacent the top surface of the core layer of the integrated photonic waveguide such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being integrated with the grating coupler and adapted to refract the light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating, 
 
       the method comprising:
 refracting light emerging from the optical element in the first coupling direction into a second coupling direction using the refractive element integrated with the grating coupler; and 
 coupling light refracted in the second coupling direction via the grating coupler, 
 wherein the first coupling direction is perpendicular to an average plane of the substrate on which the waveguide is disposed. 
 
     
     
       12. A device according to  claim 1 , wherein the optical element is an optical fiber. 
     
     
       13. A device according to  claim 1 , wherein the second coupling direction is in the range of 10° to 40° from normal to the average plane of the integrated photonic waveguide. 
     
     
       14. An integrated photonic device operatively coupleable with an optical element in a first coupling direction, the integrated photonic device comprising:
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate; 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the core layer of the waveguide into a second coupling direction different from the first coupling direction; and 
 a wedge-shaped refractive element adjacent the top surface of the core layer of the integrated photonic waveguide such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being integrated with the grating coupler by being directly formed in the integrated photonic device and adapted to refract the light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating. 
 
     
     
       15. A device according to  claim 14 , wherein the first coupling direction is perpendicular to an average plane of the waveguide. 
     
     
       16. A device according to  claim 15 , wherein the second coupling direction is in the range of 10° to 40° from normal to the average plane of the integrated photonic waveguide. 
     
     
       17. A device according to  claim 14 , wherein the refractive element comprises a plurality of sub-elements, each sub-element being adapted for refracting part of the light emerging from the grating coupler in the second coupling direction into the first coupling direction. 
     
     
       18. An integrated photonic device operatively coupleable with an optical element in a first coupling direction, the integrated photonic device comprising:
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate; 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the waveguide into a second coupling direction different from the first coupling direction, the grating coupler comprising a grating; and 
 a refractive element disposed in direct contact with the grating coupler by being directly formed in the integrated photonic device such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being adapted to refract the light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating. 
 
     
     
       19. An integrated photonic device according to  claim 18 , wherein the refractive element is a wedge-shaped element integrated with the grating coupler. 
     
     
       20. A method for fabricating an integrated photonic device according to  claim 18 , the method comprising:
 providing a photonic device comprising
 an integrated photonic waveguide comprising a core layer having top surface and a bottom surface, the integrated photonic waveguide being disposed on a substrate with its bottom surface facing the substrate, and 
 a grating coupler formed in the top surface of the core layer of the integrated photonic waveguide, the grating coupler being adapted for diffracting light from the core layer of the waveguide into a second coupling direction different from the first coupling direction, the grating coupler comprising a grating; and then 
 
 directly forming in direct contact with the grating a refractive element such that the grating is between the core layer of the waveguide and the refractive element, the refractive element being adapted for refracting light emerging from the grating coupler in the second coupling direction into the first coupling direction, the refractive element having a refractive index different from the material of the grating. 
 
     
     
       21. A method according to  claim 20 , wherein directly forming the refractive element in direct contact with the grating includes molding the refractive element directly on the photonic device. 
     
     
       22. A method according to  claim 21 , wherein the refractive element is made of polymer. 
     
     
       23. A method according to  claim 22 , wherein directly forming the refractive element in direct contact with the grating includes
 providing a mold having a wedge-shaped indentation; 
 disposing a curable material on the grating or on the mold; 
 bringing the mold into contact with the photonic device, aligning the wedge-shaped indentation of the mold with the grating, such that the curable material substantially fills the wedge-shaped indentation of the mold; 
 curing the curable material to form a wedge-shaped refractive element; and 
 removing the mold from the wedge-shaped refractive element. 
 
     
     
       24. The method according to  claim 20 , wherein the first coupling direction is perpendicular to an average plane of the substrate on which the waveguide is disposed. 
     
     
       25. An integrated photonic device according to  claim 3 , wherein the grating coupler comprises grooves formed in the integrated photonic waveguide, and wherein the material of the refractive element is a molded material filling the grooves of the grating. 
     
     
       26. An integrated photonic device according to  claim 25 , wherein the refractive element is made of polymer.